Shape fixing abilities of SEBS/Paraffin blends with different paraffins under conventional and reversible plasticity shape memory programming

Poly(styrene-b-[ethylene-co-butylene]-b-styrene) (SEBS)/paraffin system is a promising class of shape memory polymers and the transition temperature of such materials could be flexibly regulated by choosing different paraffins. However, the difference in shape memory performance of SEBS/paraffin blends containing paraffin with same content but different melting temperature ( T m ) has not been comparatively studied. In this work, two series of SEBS/paraffin blends containing same content paraffin (30 and 70 wt%, respectively) with T m of 28.5 and 61.3 °C (denoted as P L and P H , respectively) were prepared and their shape fixing ratios (R f s) under conventional shape memory (CSM) and reversible plasticity shape memory (RPSM) programming methods were investigated. It was found that these blends with the same paraffin content showed different R f s regardless of the programming method. For example, the 30 wt% P H -containing sample exhibited higher R f under CSM programming, while the 70 wt% P L -containing sample showed higher R f under RPSM programming. By investigating microstructural changes, a possible explanation for the shape memory performance of SEBS/paraffin blends containing paraffin with different T m was proposed. This work was helpful to deepen the understanding of shape memory mechanism and broaden the application of SEBS/paraffin-based shape memory polymers.